On trial for assault, officer describes details of beating

What the tape shows after that lies at the heart of the trial and yesterday’s testimony.

In the video, DeCarlo is seen quickly walking up to Mendonca before kicking and hitting him. Prosecutors say the detective broke protocol and brutally assaulted the handcuffed 22-year-old, striking him in the back of the head with a flashlight. The flashlight blow put Mendonca in a coma for two days, his lawyer and family have said.

DeCarlo, 46, told jurors that he was using approved police procedure to subdue someone he believed was a dangerous suspect resisting arrest.

DeCarlo testified that it was too dark to see Mendonca was in handcuffs and that when he approached, it sounded as though the suspect was struggling with police officers, who had been investigating a break-in at the Rhode Island School of Design. He said he felt terrible and disgusted once he realized his mistake. “I couldn’t believe I used this kind of force on this guy who was already handcuffed,’’ DeCarlo told jurors.

He also testified that he believed he had struck Mendonca’s upper back, not his head.

“I figured I’d get one more shot in,’’ he said. “The top of his back was exposed to me, and I figured if I could get a shot in there he might go down to the ground.’’ DeCarlo said he was not aware that he had made contact with his flashlight.

Defense attorneys have argued that Mendonca may have sustained the injury prosecutors attribute to the flashlight after he fled from police, possibly while trying to hide under a car.

Prosecutors are set to cross-examine the detective today.

Mendonca was convicted of assaulting two Rhode Island School of Design security officers.